Telephone system.



M. BAUMER.

TELEPHONE SYSTEM. APPLICATION FILED NOV. 24, 190B.

928, 17 1 Patented July 13, 1909; 3 BHEETSSHEBT 1. Exchang M 0 cm.

M. BAUMER. TELEPHONE SYSTEM.

APPLICATION FILED NOV. 24. 1903.

928,171. Patented July 13, 1909.

3 BKEET8SHEET 2.

Subslalwn B Subs'lalion C.

- SufislalionA.

MORIZ BAUMER, OF NUREMBERG, GERMANY.

TELEPHONE SYSTEM.

To all whom it may concern:

Be it known that I, Moniz BAUMER, a subject of the King of Bavaria, residing at Nuremberg, German Empire, have invented certain new and useful Improvements in Telephone Systems, of which the following is a specification.

My invention relates to switching apparatus for an automatic branch exchange switching system, in which there is no relay carrying a permanent current connecting the substations with the main line, but in which, for the purpose of starting the automatic intermediate switching station from a substation, tip relays, each having two coils, are employed. The one coil, for the purpose of bringing the armature into the working position, is connected on the one hand over the armature to the corresponding branch line of the substation calling up for the time being, and on the other hand over backcontacts and the armature of a separating relay, used for all the tip-relays in common and grounded over a battery. The second coil of each tip-relay, for the purpose of returning its armature to the position of rest, is connected to the working contact of a step-back relay, excited by the clearing current, whose armature is connected to the nongrounded pole of the battery at the automatic intermediate switching station.

In the acconnpanying drawing, Figure 1 is a diagram of the existing exchange connections, Fig. 2 is the automatic intermediate switching apparatus, and Figs. 3, i and 5 are diagrams showing already existing subscribers apparatuses. Fig. 6 is a detail View illustrating the relayactuated pawl and ratchet mechanism for the springs of the intermediate switch.

At the exchange (Fig. 1), SE is a transmitter with call key AT, and step-back key RT At the subscribers apparatuses, (Figs. 3, 4t and 5), C are condensers, GW record alarms, AT call keys and RT step-back keys.

The operation is as follows 1. Assume that from a telephone call 400, not shown in the drawing and lying outside the group, it is desired to communicate with the substation 2000 C. The subscriber 400 calls up the exchange in the ordinary manner, whereupon the call-indicator at the latter drops. The oiticial inserts the inquiry plug AS (Fig. 1) into the inquiry jack, puts the speaking switch SH into the listening position and makes the inquiry. The sub Specification of Letters Patent.

Application filed November 2%, 1908.

Patented July 13, 1909.

Serial No. 464,329.

scriber 400 requests connection with the substation 2000 C connected in the common line a Z), whereupon the official inserts the connecting plug VS into the jack VK, by which means the connection with the common line a Z) and automatic intermediate switch ZU (Fig. 2) is made. In order to get the connection with the substation 2000 C, the oiiicial now sets the transmitter SE (Fig. 1) to the group position C, but leaves the speaking switch SH. in the listening position. A contact 4-3 is thus closed and the line a connected with the line b. The transmitter SE (which may for instance be spring actuated) returns automatically from the position C to the position of rest and closes three contacts in succession 44 C, B, A. At each of these contacts there results the following circuit: earth, battery AB, transmitter SE, contact at C (or B or A), line a, and simultaneously contact 43, line 6, over contacts 541, of the speaking switch SH, contacts R 52, 53, connecting plugs VS 59, 60 and multiple jacks VK 63, 64, through the common line a b, the two coils of the adjustment relay ER, intermediate switch ZU (Fig. 2), and earth, back to the exchange battery AB. Owing to the three rushes of current the three springs F, F F at the intermediate switch are advanced three steps, by actuation of the pawl-armature of the relay ER (Fig. 6). The springs F and F now rest on the contact studs K K of the distributing disk VScZL and the lines a Z) are connected with the lines L L, leading to the substation C. The spring F rests at this moment on a segment 0 b of the distributing disk VScZL and the following circuit is closed: switching battery UB, coil of separating relay TR, spring F segment 0 Z), switching battery UB. The armature in the separating relay TB is thus attracted, three contacts 4t, 5, 6 are broken and the three relays URA, URB, UR-C are cut off from the battery UB. The substation G now lies in the line a 6 over the two springs F, F contacts K K and lines L L The official in order to call up the substation C now depresses the call key AT, (Fig. 1) at the transmitter SE and then turns the speaking switch SH back again. In this manner the following circuit is closed: alternator RM, call key AT contact a5, call key contacts R 50, 52, connecting plug VS 59, jack VK 63, common line a, spring (Fig. 2), contact button K subscriber line L,, re-

ceiver hook TI-I (Fig. 5), condenser CO, alternate current alarm coil IV, earth, back to the exchange (Fig. 1), contact e6, call key AT and alternator RM. The alarm IV (Fig. 5) at the substation 2000 O rings. The subscriber unhooks his receiver and conversation can commence. On the call being given a branch circuit current flows to earth through the line a and the one coil of the adjusting relay, but remains ineffective,

since the relay ER does not respond through the half coil. When the conversation is ended, the subscriber 2000 O hangs up his receiver and depresses the step-back key RT (Fig. 5), simultaneously turning the crank of the magneto IN, whereupon the following circuit is completed: subscribers magneto IN (Fig. 5), subscribers line L contact stud K (Fig. 2), spring F common line 6, jack VK 6 1 (Fig. 1), connecting plug VS 00, call key It 53, operating switch SH 54, clearing relay SR, speaking switch SH 55, call key R 52, connecting plug VS 59, connecting jack VK 63, line a, spring F (Fig. 2), contact stud K subscriber line L,, contact 31 of the step-back key RT (Fig. 5), magneto IN. The ring off indicator at the exchange drops, and the following branch circuit is also closed: intermediate switch ZU (Fig. 2), line Z), step-back relay RR, condenser CO line a. The pawl-armature in the step-back relay RR (Fig. (3) is attracted, whereby the springs F, F F and also the armature of the separating relay TR, return into the position of rest. The contacts 1, 5, (3 are again made and the relays URA, URI URO are again connected with the earth through the intermediate switch battery UB. By attraction of the step-back armature RR a contact 11 is closed and a current flows from the positive pole of the battery UB, contact 11, all the parallel-connected coils II of the relays URA, URI URO, back to the minus pole of the battery UB. The armatures of the relays UR are attracted, but as they have not hitherto operated they are already in their position of rest. The oflicial now pulls the plugs VS and AS out of the jacks, whereupon the position of rest is again assumed.

2. Suppose, on the other hand, the subscriber at 2000 O wishes to call up the subscriber at 100, lying outside this group and not shown in the drawing. Assume that the common line (a b is unoccupied. The subscriber 2000 O turns the record switch VH (Fig. to the left, connecting the alarm GW with the substation wire L whereby the following circuit is made: battery UB (Fig. 2), armature of the separating relay TR, contact 6, coil I of the relay URO, contact 8 of the armature thereof, substation line L alarm GI/V (Fig. 5), record switch VH, earth, back to battery UB (Fig. 2). The alarm GVV rings to show that the line a b to the exchange is unoccupied. In the relay URO no effect is produced, owing to the high resistance of the coil I and to the alarm being cut in. The subscriber now turns the record switch VII (Fig. to the right again, depresses the call key AT and turns the crank of the magneto IN, so that the following circiut is closed: magneto IN (Fig. 5), line L armature of the relay URO (Fig. 2), contact 3, coil I, contact 6, armature of separating relay TR, through battery UB to earth, earth (Fig. 5), contact 30, call key AT and magneto IN. The armature of the relay URO (Fig. 2) will now, despite its high resistance, owing to alarm OW being cut out, on the first rush of current be tipped to the left, whereby two contacts 16, 17 will be made and the contact 3 broken, so that the current flows from the magneto IN (Fig. 5) through the line L armature of the relay URO (Fig. 2), contact 16, common line b to the call indicator AR (Fig. 1). In this manner the subscriber 2000 O has connected himself with the common line b and the call has been given at the exchange. The interruption at the contact 3 of the current flowing through the coil I is of no consequence, since the double armature always remains in the position given it for the time being. Owing to tipping of the double armature of the relay URO (Fig. 2) a contact 20 will also be made, so that the following curcuit is closed: battery UB, coil of the separating relay TR, contact 20, battery UB. The armature of the separating relay TR is attracted and the contacts 4, 5, 6 are broken, and also the extension of the lines L L used for adjusting the substations A and B over the coils I of their relays URA, URB. It is thus rendered impossible for these subscribers to connect themselves again with the common line a 7), or to disturb the existing connection. After the call indicator at the exchange has dropped, the otlicial inserts the inquiry plug AS (Fig. 1) into the jack AK, turns the speaking switch SH and inquires. The subscriber has meanwhile taken off his receiver from the hook and has requested connection with No. 400. The official gives the connection with No. 400 in the usual manner and the conversation can commence from the subscriber 400, main line at, intermediate switch ZU, contact 17, substation line IJ, substation 2000 C, receiver hook TH, induction coil S, receiver, magneto IN, common line Z), over the exchange to apparatus of subscriber 4.00. On conclusion of the conversation the subscribers hang their receivers on the hooks again and ring olf. The return of the intermediate switch ZU to the position of rest and the clearing signal at the exchange can be given by the ringing off either of the subscriber 400 or subscriber 2000 C. The subscriber 2000 G for this purpose depresses the step -back key RT (Fig. 5), turns the crank of the magneto IN and thus completes the follow ing circuit: magneto IN, line L armature of the relay URC (Fig. 2), contact 16, common line 2), jack AK (Fig. 1), inquiry plug AS 58, call key It 51, speaking switch SH 5e, coil of ring oft indicator SR, speaking switch SH 55, call key It 50, inquiry plug AS 57, jack AK 61, common line a, contact 17 (Fig. 2), insulated spring of the armature of the relay URG, substation line L contact 31 (Fig. 5), step-back key RT, magneto IN; in this manner the clearing out indicator at the exchange is caused to drop. A substation current flows through the common line a to the condenser CO (Fig. 2), coil of the step-back relay RR and line b. In this way the armature of the step-back relay is attracted and the contact 11 closed, whereby the following circuit is completed: battery U1), armature of step-back relay RR, con tact 11, coils 11 of all the relays URA, URB, URC and back to battery UB. The armatures of these relays are attracted toward the right; at the armatures URA, URB no effect is produced, since they lie in the right hand position already. On the other hand, the armature of the relay URC, which was attracted to the left, will now be tipped over to the right. The contacts 16, 17 are broken and the common line a Z) is separated from the substation line L L Furthermore, the contact 20 is broken and the separating relay TR thus rendered currentless, whereby its armature returns to the position of rest and the contacts 4, 5, 6 are again made. The contact 3 will likewise be made again by tipping of the armature of the relay URU, so that the substation lines L 11,, L with the coils I of their relays URA, URB, URC are again earthed by the battery UB. The subscribers of the substations A B C can thus connect themselves with the comm on line 0. 6 again. Had the subscriber 400 first rung off, he would as hitherto usual, have sent an alternating current into the line, whereby the ring-01f indicator at the exchange would drop. From this alternating current, which would also have passed through the common line a b, a substation current would have flowed from the line a to the condenser ()0 and the coil of the step-back relay ltlt to the line b, which would have produced the same effects as the magneto current which the subscriber 2000 C has sent through the line as above described.

3. Assume now that the subscriber at the substation 2000 A. wishes to speak with the subscriber 2000 G, the common line a 6 however being occupied. The subscriber 2000 A turns the record switch VH (Fig. to the left and the alarm GVV does not ring: the line is therefore occupied. The circuit which is intended to ring the alarm GFW has not been completed owing to the separatat the exchange.

ing relay TR having attracted its armature. The subscriber 2000 A turns the record switch VH to the left and waits. After the foreign conversation has been concluded the armature of the separating relay TR (Fig. 2) drops into the position of rest again. The circuit of the alarm GJV is closed and the latter rings. The subscriber 2000 A is thus informed that the line is unoccupied, henow turns the record switch VH (Fig. 3) back again and thus breaks at Vl-l the following circuit: battery UB (Fig. 2), armature of separating relay TR, contact 4-, coil 1 of the relay URA, contact 1, armature of the relay UHA, substation line L alarm GV (Fig. 3), record switch t T, earth, earth (Fig. 2), back to battery UP), whereby the alarm ceases to ring. The subscriber at 2000 A now depresses the call key AT (Fig. and turns the crank of the magneto 1N, this magneto current flows as follows: magneto 1N, line L armature of relay Ultra (Fig. 2), contact 1, coil I of the same relay, contact 1, armature of separating relay TR, through battery UB to earth, earth (Fig. 3), contact 30, call key AT, back to magneto TN. The armature of the relay URA (Fig. 2) is tipped to the left, contact 1 is broken and contact 12 closed. The current now flows from the magneto 1N (Fig. 3), line L armature of relay UB1! over contact 12, common line i), coil of call indicator Alt (Fig. 1) to earth, earth (Fig. 3), contact 30, call key AT, back to magneto TN. 111 this manner the call indicator drops By tipping of the armature of the relay Ultrr (Fig. 2), besides the contact 12 there are two other contacts 13, 18 closed. By contact 13 the substation line L, is connected to the common line a, so that the substation 2000 A is connected through the lines L L ari'nature and spring of relay UEA and contacts 12, 13, with the con'nnon line a b.

By closing the contact 18 the following circuit is made: battery U13, coil of separating relay TR, contact 153, battery U15. The armature of the separating relay is attracted, the contacts t, 5, 6 broken and thus the substation line branch L L, separated from earth, as already above described in detail. When the call indicator AR at the exchange has dropped, the otlicial inserts the inquiry plug AS (Fig. 1) into the jack AK, turns the speaking switch SH and makes the inquiry. The subscriber 2000 A has meanwhile removed his receiver and asks for call 2000 G. The oliicial now leaves the speaking switch SH in the listening position, and sets the transmitter SE to C, contact 43 is closed and the line athus connected with line Z). The transmitter SE, being spring actuated, returns automatically from the position 0 to its position of rest: it thus closes three contacts in succession, viz. 44 C, B, A; at each of which the following current flows: exchange battery AB (Fig. 1), transmitter SE, contact 4L4: C (or B, or A), line a, contact 43, line Z), that is to say, simultaneously through both lines a and Z), over the contacts 5 1-, 5:) of the speaking switch SH, inquiry plug AS 57, 5S and inquiry ack AK 61, 62 and through the common line a Z) to the two coils of the adjusting relay ER- (Fig. 2), to earth, earth (Fig. 1), battery AB. By means of these three rushes of current the springs F, F F (Figs. 2 and 6) are ad- \anccd three steps, the springs F, F now resting on the contact studs K K with which the substation lines L L are connected. The spring F which rests on the segment 0 7), could not close the circuit: battery UH, coil of separating relay TR, spring F segment 0 a, battery U13, because it has already been closed on connection being made with substation 2000 A. The substation 0 is thus connected with the common line a Z) by the substation lines L L contact studs K K and springs F F,, that is, over the distributing disk VSch, while the substation A is connected with the common line a 7) over the relay URA. The otlicial now depresses the call key AT (Fig. 1) and thus calls up the substation 2000 C. The circuit completed is follows: alternator RM (Fig. 1), call key AT contact 45, inquiry plug AS 57, inquiry jack AK (31, common line a, spring F (Fig. 2), contact stud K substation line L receiver hook TH (Fig. 5), condenser CO, alternating current alarm N, earth, earth (Fig. 1), contact it all key AT alternator RM. The alarm V of the substation 2000 C rings, the subscriber goes to the apparatus, unhooks the receiver and the conversation can commence. When the conversation is concluded the subscribers 2000 A and 2000 G hang up their receivers again on the hooks and ring oil". Assume that the subscriber 2000 A is the first: He depresses his step-back key RT (Fig. 3), turning the crank of his magneto IN simultaneously. In this manner the following circuit is closed: magneto IN (Fig. 3), sub station line L armature of the relay URA (Fig. 2), contact 12, common line 0, inquiry jack AK 02 (Fig. 1), inquiry plug AS call key R 51, speaking switch SH 54:, (which has meanwhile been reversed) coil of the ring o'tli indicator SR, speaking switch SH 55, call key 50, inquiry plug AS 5?, jack AK 01, common line a, contact 18 (Fig. 2), insulated spring of the armature of the relay URA, substation line L contact 31 (Fig. 3), step-back key RT, magneto IN. The ring ofl' indicator SR thus drops. The following branch circuit is also closed: common line a, condenser CO (Fig. 2), coil of the step-back relay RR, common line b. The armature at the step-back relay RR is attracted, the springs F, F F (Figs.

2 and return in consequence to their position of rest and the contact 11 is closed, whereby the following circuit is completed: battery UB, armature of the step back relay RR, contact 11, all the coils II of the relay URA, URB, URC, battery UB. The armatures of the relays URA, URB, URC are drawn to the right; at URB, URG therewill be no result, since the armatures of these relays are already in the right hand position the armature of the relay URA, on the other hand, which has been lying toward the left, is now tipped toward the right, the contacts 12, 13 are interrupted and thus the substation lines L L of the common lines a Z) separated; the contact 18 will likewise be broken, so that no current will pass through the separating relay TR. The armature of the latter will return to its normal position and the substation lines L L L will, with the coils I of their relays be again connected to earth. Had it been the subscriber 2000 C who first rang oii, the return to the step-back position would have been effected in the same manner, except that in this case the magneto current instead of flowing through the contacts 12, 13 of the relay USA would have passed over the contacts K K and springs F, F of the switch ZU, to the common line a Z). If, whether accidentally or with intention, the step-back position has not been brought about by either subscriber, the ring otl' indicator at the exchange does not drop. The otlicial will then inquire after some time, and if no reply is received she must bring about the step-back position herself, before drawing out the plug. Similarly the otlicial can interrupt the conversation if a long-distance line is required for a subscriber of the common line a b.

For the purpose of effecting the step-back position, or the interruption, the otticia must l are the speaking switch SH turned to listening and depress the step-back key RT (Fig. 1) at the transmitter. In this manner the following circuit is completed: alternator RM, contact 41, upper spring of the step-back key 3T transmitter SE, line a, speaking switch SH 55, call key R 50, inquiry plug AS 57, jack AK 61, common line a, condenser CO, (Fig. 2), coil of the stepback relay RR, common line 6, jack AK 62 (Fig. 1), inquiry plug AS 58, call key R 51, speaking switch SH 54, line 6, lower spring of the step-back key RT,, contact 40, alternator BM. in this manner the armature of the step-back relay RR (Fig. 2) is attracted and the step-back position produced in the same way as already above described. On depression of the step-back key RT (Fig. 1), the contact 42 and thus the line to the receiver T of the otlicial will now be broken, so that there is no rush of current to the receiver.

Having thus described my invention, I declare that what I claim is 1. In a telephone switch apparatus for an automatic branch exchange switch system, a rotary switch instrument and an adjusting relay operating with current impulses from the exchange for the purpose of connecting the subscribers apparatuses; tip-relays, one corresponding to each subscribers apparatus and having two coils, the one end of the first coil, to enable the subscriber to bring the armature of said relay into the working position, being connected with the tiprelay armature, said armature being connected with the subscribers line; a separating-relay whose armature is furnished with back-contacts, one corresponding to each subscriberstation and connected with the other end of said coil; an earthed battery in circuit with last-named relay and its armature; a clearing out circuit; and a step-back relay 0perated by the clearing-current, whose armature is furnished with a working-contact, which to enable the subscriber to return the tip-relay to its position of rest, is connected wit-h the one end of the second said tiprelay coil, whose other end is grounded, while the armature of said step-back relay is connected with the non-grounded pole of said battery, substantially as described.

2. In a telephone switch apparatus for an automatic branch exchange switch system, a rotary switch instrument and an adjusting relay operating with current impulses from the exchange for the purpose of connecting the subscribers apparatuses; tip-relays, one corresponding to each subscribers apparatus and having two coils, the one end of the first coil, to enable the subscriber to bring the armature of said relay into the working position, being connected with the tip-relay armature, said arnlature being connected with the subscribers line; a separating-relay whose armature is furnished with back-contacts, one corresponding to each subscriber-station and connected with the other end of said coil; an earthed battery in circuit with last-named relay and its armature; a clearing out circuit; and a step-back relay operated by the clearing current, whose armature is furnished wit-h a working-contact, which to enable the subscriber to return the tip-relay to its position of rest, is connected with the one end of the second said tip-relay coil, whose other end is grounded, while the armature of said step-back relay is connected with the non-grounded pole of said battery; a contact-piece carried by, but insulated from, each tip-relay armature and connected to the earthed-battery through the separating-relay coil; and a back-contact for each tip-relay armature, connected with the ground side of said battery; and means for grounding the line at the subscribers stations; whereby 011 the exchange being called up by a subscriber the corresponding tip-relay armature is brought into its work- MORIZ BAUMEI.

WV itn esses O'r'ro HAnrNen, PAUL DoLLiuorn. 

